The incorporation of electronic devices with pneumatic tire structures yields many practical advantages. Tire electronics may include sensors and other components for obtaining information regarding various physical parameters of a tire, such as temperature, pressure, number of tire revolutions, vehicle speed, etc. Such performance information may become useful in tire monitoring and warning systems, and may even potentially be employed with feedback systems to regulate proper tire pressure levels.
A potential capability offered by electronics systems integrated with tire structures is asset tracking and performance characterization for commercial vehicular applications. Commercial truck fleets, aviation crafts and earthmover/mining vehicles are all viable industries that could utilize the benefits of tire electronic systems and related information transmission. Tire sensors can determine the distance each tire in a vehicle has traveled and thus aid in maintenance planning for such commercial systems. Vehicle location and performance can be optimized for more expensive applications such as those concerning earth-mining equipment.
U.S. Pat. No. 6,388,567 (Bohm et al.) discloses a monitoring device and patch combination used to monitor the conditions of a tire. The patch portion houses an antenna and is securely mounted to the innerliner of a tire. The monitoring portion, which may be separately fabricated from the patch portion, includes sensors and other circuitry to monitor various parameters related to the tire and includes a battery fully encased with the monitoring circuitry. Another example of a mounting arrangement for an electronic tire monitoring-system can be found in U.S. Pat. No. 6,309,494 (Koch et al. '494), which concerns a method of attaching electronic equipment to the inner surface of a tire. The method involves the use of an epoxy adhesive to directly bond the monitoring device to the inner surface of the innerliner of the tire.
Yet another example of a mounting arrangement for an electronic tire monitoring system can be found in U.S. Pat. No. 6,255,940 (Phelan et al.), which discloses another patch and monitoring device combination. The patch portion of the combination includes a nut secured within a central portion of the patch for receiving a matching bolt. The monitoring portion of the combination includes a module containing various sensors, a battery and other circuitry all encased in an epoxy and glass bead mixture. Mounted within this module is a nut, similar to the nut contained within the patch portion, such that the monitoring portion may be attached to the patch portion after the patch portion is securely attached to an inner surface of the tire. A further example of a mounting arrangement for an electronic tire monitoring system can be found in U.S. Pat. No. 6,087,930 (Kulka et al.) which discloses an active integrated circuit transponder and sensor apparatus all encased in a unitary housing. The monitoring system includes an integral battery and the entire arrangement may be inserted directly within the sidewall of a tire to be monitored or configured as a patch so be secured to an inside surface of the tire to be monitored.
Yet a further example of a mounting arrangement for an electronic tire monitoring system can be found in U.S. Pat. No. 6,030,478 (Koch et al. '478), which discloses a method and apparatus permitting the insertion and removal of an electronic monitoring device from a tire. Such patent discloses a technique wherein a vulcanized rubber patch is permanently assembled to the inner liner of a tire and an electronic monitoring device, which has been encapsulated in a rigid potting material and fitted with a battery, is inserted into a cavity in the patch.
The disclosures of all of the foregoing United States patents are hereby fully incorporated into this application for all purposes by reference thereto.
One concern associated with the use of tire monitoring patch and electronics combinations like those of the above-noted prior art involves the secure attachment of the combinations to the tire. As in the cases of Bohm et al., Phelan et al., and Koch et al. '478 noted hereinabove, a solution has been provided involving the use of a separate supporting/attachment patch and a physically separate electronics package or module. Alternatively, other solutions to the attachment problem provide unitary devices that may be directly secured to the tire as in Koch et al. '494 and Kulka et al.
A second concern associated with the use of tire monitoring patch and electronics combinations like those of the above-noted prior art results from the inclusion of a relatively heavy battery within the electronics package or module. The need to support a relatively heavy battery together with the other circuitry associated with the electronics portion of the tire monitoring and electronics combination requires a physically robust mounting structure such as, for example, the nut and bolt arrangement of Phelan et al.
Another concern associated with tire monitoring patch and electronics combinations relates to wireless signal transmission from an RF device associated with the tire electronics to a receiver external to the tire. Often the signal path through the tire and mounting structures is degraded, sometimes in part due to the materials and configuration of the tire and mounting structures for the antennas associated with the data transmitters within the electronics portion of the monitors. Effective signal propagation in hardwired connections among electronic devices in a tire must also preferably be ensured.
Yet another concern associated with tire monitoring patch and electronics combinations relates to the fact that the patch or mounting portion of the combination must be flexible in order to adapt to the rotational movement of the tire while in use. Because of this required flexibility, care must be taken that the internal connections of the electronic circuitry are not disrupted or impaired due to continual flexing of the patch.
While various tire monitoring patch and electronics systems have been developed, no one design has emerged that generally addresses all of the above-referenced concerns and that encompasses all of the desired characteristics as hereafter presented in accordance with the subject technology.